A scroll compressor is a certain type of compressor that is used to compress refrigerant for such applications as refrigeration, air conditioning, industrial cooling and freezer applications, and/or other applications where compressed fluid may be used. Such prior scroll compressors are known, for example, as exemplified in U.S. Pat. No. 6,398,530 to Hasemann; U.S. Pat. No. 6,814,551, to Kammhoff et al.; U.S. Pat. No. 6,960,070 to Kammhoff et al.; and U.S. Pat. No. 7,112,046 to Kammhoff et al., all of which are assigned to a Bitzer entity closely related to the present assignee. As the present disclosure pertains to improvements that can be implemented in these or other scroll compressor designs, the entire disclosures of U.S. Pat. Nos. 6,398,530; 6,814,551; 6,960,070; and 7,112,046 are hereby incorporated by reference in their entireties.
As is exemplified by these patents, scroll compressors conventionally include an outer housing having a scroll compressor contained therein. A scroll compressor includes first and second scroll compressor members. A first compressor member is typically arranged stationary and fixed in the outer housing. A second scroll compressor member is moveable relative to the first scroll compressor member in order to compress refrigerant between respective scroll ribs which rise above the respective bases and engage one another. Conventionally, the moveable scroll compressor member is driven about an orbital path about a central axis for the purposes of compressing refrigerant. An appropriate drive unit, typically an electric motor, is provided usually within the same housing to drive the movable scroll member.
To support the high speed rotation of a drive shaft within a scroll compressor, shaft bearings are conventionally employed as shown in the above-mentioned patents and as discussed in some detail in U.S. Pat. No. 6,109,899. As discussed therein, a bearing incorporates a composite resin material that includes a graphite and a heat resistance resin complex layer that includes hard carbon particles deposited into a resin base. The bearing indicated is said to be made by Taiho Kogyo, Ltd. under the trade name, “Carbon Composite Bimetal Bearings CB 100G”, which is formed of a material that is a hard thermoset resin that is irreversibly cured. Such a thermoset material cannot be melted or re-shaped after it is cured. As a result, and in such applications as a scroll compressor, this material requires further machining processes to provide for a precision fit and alignment between the shaft and bearing surfaces of the upper and lower bearing members and the drive hub of the movable scroll member. Thus, while there are some advantages to this approach, one of the draw backs of this approach is the additional cost and complexity associated with the need to machine the bearing surface to provide for a highly precise fit between the shaft and the bearing surfaces.
More conventionally in scroll compressors, cylindrical bearings will be lined with some of the following materials: bronze, leaded bronze, babbitt alloy, PTFE, PTFE composite (with lead and/or trace amounts of silicon oxide—believed to be less than 1% by volume). Despite many years and many different materials tried for bearing materials in such scroll compressors, it is still believed that there is a substantial deficiency in the present state of the art, and the present invention is directed towards improvements over the state of the art.